New international research led by The Hospital for Sick Children (SickKids) provides evidence that in addition to an excellent chance of survival, newly-diagnosed children with standard-risk acute lymphoblastic leukemia (ALL) are also likely to live healthy lives with few long-term complications into adulthood. The study is published in the June 20 online edition of Lancet Oncology.
Over the past 20 years, survival rates of standard-risk childhood ALL have climbed to their current rate of more than 90 per cent. Experts attribute this success story to the evolution of treatment protocols, which are similar across North America, Europe and other parts of the world. The therapies that are used today are less harsh than their predecessors; the current protocols have eliminated radiation in children with standard-risk ALL, and have restricted the use of certain chemotherapy drugs that may cause subsequent cancers and other chronic health conditions. Previous research had only assessed the very long-term outcomes of children treated with older protocols, leaving physicians to piece together information from this outdated data and anecdotal evidence.
“This is one of the first studies to show that in addition to their excellent probability of survival, long-term survivors of standard-risk childhood ALL are at low risk for complications of their therapy once they enter adulthood,” says Dr. Paul Nathan, principal investigator of the study, Director of the Aftercare Program in Haematology/Oncology and Senior Associate Scientist at SickKids.
Researchers used longitudinal data from the Childhood Cancer Survivor Study, a multi-centre North American study of five-year survivors of childhood cancer diagnosed between 1970 and 1986. The research team included 556 people from this group who were over age one and under age 10 at the time of diagnosis and who had received treatment consistent with current therapies for standard-risk ALL. The group was followed from five years following diagnosis to a median of 18 years. The survivor group was compared with a group of their siblings who had not had cancer, and the general population.
They found 28 people in the survivor group died, of which 16 were due to causes other than relapse. Survivors were at a slightly increased risk of death due to non-relapse causes; however, no individual cause was increased. Six survivors developed another cancer. While the risk for most chronic health disorders did not differ between survivors and siblings, survivors appeared to have a moderately increased risk for osteoporosis or osteopenia, short stature, and cataracts. Survivors and their siblings had similar socioeconomic outcomes, including education, rates of marriage, independent living, and household income.
While the prognosis may be favourable, Nathan notes that survivors should receive ongoing care from a knowledgeable primary-care practitioner.
“Among kids with standard risk ALL, we expect most to survive. Now we can say with more certainty that they will probably do well in the long-term as well,” says Nathan, who is also Staff Oncologist and Associate Professor of Paediatrics and Health Policy, Management & Evaluation at the University of Toronto. “This information will be very useful for oncologists counselling newly-diagnosed patients and their families, and will be quite reassuring to parents.”
The research was supported by the National Cancer Institute, Cancer Center Support, American-Lebanese-Syrian Associated Charities, Swiss Cancer Research and SickKids Foundation.